EXPERIENCES WITH THE IBM SP1

One of the first IBM parallel processing computers-the SP1(TM)-and the largest, with 128 nodes, was installed in 1993 at Argonne National La boratory. It took only days, not months, to prepare for and migrate ap plications to this parallel supercomputer, demonstrating that high per formance, parallelism, and portability can coexist. This paper describ es the early experiences with the SP1 at Argonne, which provide lesson s for supercomputer system designers and users alike. We explore what features of software technology and system architecture enabled immedi ate and successful use of the SP1. The paper concludes with a brief in dication of why the move to the SP2(TM) software environment using the SP2 communication adapters, the use of the emerging Message-Passing i nterface standard, and the continued use of the SP1 processors have be en successful.